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Last week, the Rosetta spacecraft crashed into comet 67P/Churyumov-Gerasimenko after orbiting it since 2014. It was supposed to do that: the mission was at an end, and the mission designers wanted to end it by getting a close look at the surface of the comet. But this raises an interesting problem: how do you get a device that is designed to never stop to actually stop?

A spacecraft like Rosetta is built from the ground up to keep going, to reboot and go into a backup mode, phone home and wait for instructions if it encounters a problem. This is called a safe mode, and it has saved the spacecraft several times before.

So, they used an interesting approach: they patched the software on the spacecraft to stop it phoning home. The day before it was crashed into the comet, they sent it a patch that removed the safe mode and replaced it with a passive mode that hadn’t been used since before launch, where the spacecraft would simply sit and wait for instructions if it hit a problem.

it entered this passive mode, and it will stay in this mode for as long as the batteries last, forever waiting for a command to restart that will never come…

The European Space Agency (ESA) has been able to squeeze one last photo out of the Rosetta probe.

Rosetta crash-landed onto Comet 67P/Churyumov-Gerasimenko in September 2016 and the ESA revealed the last image it captured. That snap was thought to have been taken from an altitude of about 50m, but the agency now thinks it was taken between 23.3m and 26.2m from the comet’s surface.

Now the agency has released a shot from between 17.9m–21.0m above 67P, thanks to some forensic trawling of its downloads.

The agency says that Rosetta’s last minutes saw it transmit images in six packets of 23,048 bytes apiece. After the half-dozen packets of the last image was received, the probe managed to send another three, but because the ESA’s image processing-software expected six packets it did not identify the last downloads as an image.

ESA boffins eventually trawled through the probe’s telemetry, realised they had three packets to play with and therefore a chance of securing an extra snap.